$\"\"$

The summation is $\"\"$ .

Common ratio $\"\"$ is the base of the exponential function.

$\"\"$ .

Substitute $\"\"$ in summation to find the initial term.

$\"\"$ .

$\"\"$ is upper bound minus lower bound plus one.

Here $\"\"$ .

Formula 1 of $\"\"$ partial sum of geometric series: $\"\"$ .

Substitute $\"\"$ , $\"\"$ and $\"\"$ in the formula.

$\"\"$

$\"\"$ .

Sum of the series is $\"\"$ .

$\"\"$

Sum of the series is $\"\"$ .